Airbags, particularly so-called inflatable curtains, are fastened to the roof frame of the motor vehicle by way of fastening tabs in a vehicle structure above the window line. To this end, the flexible fastening tabs are generally held on the roof frame by way of form-locking elements employed to ensure that the rolled-up airbag remains in the assembled, collapsed, or folded state until it is activated. In order to maximize the installation space in light of the space conditions in the roof frame region, the airbag is accommodated above the fastening tabs. Such an attachment is known from WO 2005/094390 A1. One drawback of such an arrangement is that the form-locking element generally forms a sharp edge on which the fastening tab is bent when the airbag extends downward during deployment and covers the windows. This may result in local overloads in the tab and the form-locking element, as well as tearing or rupturing, which is to be avoided for safety reasons.
It is therefore one object of the present invention to provide an airbag which prevents or avoids such a risk. The airbag according to the present invention includes a flexible fastening tab having a fastening opening for attachment to a motor vehicle by means of a form-locking element, wherein a fastening region and a folding region are constructed in the tab. The fastening opening is constructed in the fastening region and a folding opening is constructed in the folding region, and the folding opening is dimensioned such that the folding region can at least partially fold over the form-locking element. The folding opening is consequently dimensioned large enough such that the folding region can be folded around the form-locking element, which extends through the folding opening, while the form-locking element itself projects through the fastening opening and attaches the fastening region to the motor vehicle. The folding opening is therefore dimensioned larger than the fastening opening.
According to one embodiment of the present invention, the fastening region and the folding region are placed on top of each other, wherein in an inactive state, the fastening opening is disposed opposite the folding opening or rests thereon.
According to another embodiment of the present invention, the fastening opening is positioned centrally in the folding opening, wherein this positioning applies to the assembled state. The present invention also provides that the folding region can be folded onto the fastening region, and that a folding line of the tab runs on the lower edge of the folding opening such that the entire region of the folding opening can be used. Folding the tab into a two-layer fastening tab has the advantage that only one material cut is required, thereby reducing logistical complexity and assembly effort.
The folding region and the fastening region of the tab can be fixed to each other and preferably are glued, welded, or sewn to each other, whereby strong connections of the folding region to the fastening region can be created in a simple manner.
In order to enable the bag and the folding region to easily fold down, the fastening region and the folding region are fixed in a line shape against each other, wherein the line-shaped fixation runs parallel or collinear to the folding axis of the folding region. The point of the fixation is located in the region of the fastening opening or beneath the fastening opening in order to provide sufficient folding space, such that the folding region can still surround the head of the fastening apparatus, and the head of the fastening means can still penetrate the region of the folding opening located above the fixation.
According to yet another embodiment of the present invention, a C-shaped material recess is constructed around the fastening opening as a folding opening, the center segment of which is disposed between the fastening opening and the bag, wherein the side segments of the folding opening extend to the form-locking element. In this way, it is possible for the fastening tab to carry out a fold and hinge function, by means of which it is possible for the fastening tab and hence the entire airbag to fold past the form-locking element (which may be a fastening clip or a screw, for example) such that no sharp edges and bending strain are applied to the fastening tab in the operating position.
According to yet another embodiment of the present invention, the side segments of the material recess facing away from the airbag can extend beyond the form-locking element in order to ensure that no contact occurs during the pivoting motion about an axis extending through the end points of the side segments. For safety reasons, it is provided that the side segments have at least a length that corresponds to the extension of the form-locking element in the tensile direction, wherein it is assumed that the extension in the tensile direction is no greater than the extension perpendicular to the fastening plane of the airbag. The length of the side segments must be large enough such that folding past the form-locking element is possible without contact therewith.
The material recess for the folding opening can be stamped in, cut out, or melted out, whereby the material recess can preferably be rounded. In the assembled state, the airbag is disposed on a first side, above the form-locking elements, for example, whereby in the event that the fastening tabs and the corresponding center segment of the C-shaped recess are not substantially horizontally arranged, the airbag in the deployed state is disposed on a different side of the form-locking element than in the assembled state.
In addition to introducing a material recess in a sewn-in tab, or in a tab constructed on the airbag, the material recess may be configured around the form-locking element between a material cutout in the bag and a tab fastened to the bag, the fastening opening being introduced in the tab in order to receive the form-locking element. The material recess is then formed by an open space that is formed between the bag and the sewn-on, welded-on, or glued-on tab. One aspect of this embodiment provides that the tab has a material strip in which the fastening opening is constructed, and at least one further material strip to which the bag is fastened. Preferably, in addition to the material strip having the fastening opening, two further material strips are constructed and sewn onto the bag such that a shape of the tab is formed similar to an E-shaped tab. The corresponding bag region has a recess in the region of the center strip such that the bag can be pivoted freely about the center strip in which the fastening opening is disposed with the form-locking element.
The bag is fastened to the folding region, and preferably it is sewn on, welded on, or glued on the folding region, whereby the fastening is preferably carried out at the end of the folding region opposite the folding line.
In a two-part refinement of the tab, fastening is carried out at the end of the folding region that is not connected to the fastening region.
Moreover, the folding opening is larger than the head region of the form-locking element in order to facilitate passage.
In the assembled state, the bag is preferably disposed such that it abuts a first side of the form-locking element. In the inflated state, the bag is disposed such that it abuts a second side of the form-locking element that is opposite the first side. Thus, after or during the inflation of the bag, the bag, and hence also at least part of the folding region, is folded over.
In the deactivated state, the bag is preferably rolled up, whereby the rolling-up action occurs in the direction away from the fastening region, and hence away from the fastening structure such as the automotive body, and the folding region is disposed on the side of the fastening region that faces away from the fastening structure of the motor vehicle.
The tab is preferably made of a woven fabric, wherein the woven fabric is preferably not made of the material of which the bag is produced. The bag fabric is generally of a higher quality and provided with a coating, and may therefore be too expensive for use as a fastening tab.
The fastening tab can be constructed separately and fastened to the airbag, whereby the tab may be made of a woven fabric that corresponds to the airbag fabric. Provided that no high thermal strain occurs in the fastening region, the tab can be made of a woven fabric that is different from the airbag fabric. The tab is therefore preferably constructed separately and fastened to the bag, e.g., the tab may be glued on, sewn on, or welded on the bag.
The folding opening, just like the fastening opening, can be stamped in, cut out, or melted out, wherein the openings in particular can be configured in a rounded shape in order to avoid tension peaks and to minimize strain applied on the woven fabric.
Additional benefits and advantages of the present invention will become apparent to those skilled in the art to which the present invention relates from the subsequent description of the preferred embodiment and the appended claims, taken in conjunction with the accompanying drawings.